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We were re-using an OEM power steering rack, converted to manual (electric assist) steering, so we also added some tack welds to the back of the steering rack mounts. Once the welding was completed on this and the rear subframe (read more below) it was sent out for powder coating.
There a gloss black powder coating was applied to give this raw steel some corrosion protection. Its a bit flashier than the factory coating, but when you have it down to the raw steel like this, powder coating is the way to go.
The front M3 spindles were also dismantled, glass bead blasted, then "double nickel plated" (a process we tried on a few suspension parts in the past, and it looks great and lasts). The spindles were treated to brand new front hubs, then some of our 90mm wheel studs. We sent the OEM front lower control arms to our friends at SPL Parts for them to model for a billet adjustable lower control arm set with spherical bearings. We should see those soon, but for now the car has the old arms back on to be able to roll around the shop.
8.8" IRS DIFF HOUSING UPGRADE & REAR SUBFRAME REINFORCEMENT
Left: Our E36 LS1 swap "Alpha" build saw tons of abuse on the 188mm BMW diff. Right: Our Beta customer broke the medium case
The argument for using a BMW diff in our swaps goes back to 2002 when we first starting our E36 LS1 "Alpha" project. And in
2011 when we kicked off the E46 LS1 development we had the discussion again, but this time with many years of first hand experience with a "medium case" E36 M3 limited slip behind a 500 whp engine and 315mm Hoosiers. We couldn't manage to break the 188mm Medium case but we did have one customer (540 whp) that did - but in his own words, he breaks everything.
This LS powered Miata used an aluminum Ford 8.8" IRS differential mounted in a custom rear subframe
In various V8 builds since then we've used a variety of solutions: the Medium case BMW diff, a Ford 8.8" diff (Miata V8, Beta E36 LS1), and even the 210mm "large case" BMW E46 M3 differential in customer E46 M3 LS swaps. This "large case" BMW unit is also used in heavier cars like the M5, 7 series, and more, and in the E46 M3 it always came with a limited slip differential.
The non-M E46 chassis got the medium case unit, and 100% of those were OPEN differentials, which while still fairly strong are not ideal for putting down power (I fight with the open diff with only 220 hp in my TTD 330). For this project the "easy button" solution would be to leave the E46 M3's larger 210mm ring gear unit in place and just upgrade the axles. And we proposed that to the owner of this car early on - but cautioned that the torque that this somewhat larger stroker LS motor can put out (700 ft-lbs) might be past the limit for this car. There are lots of BMWs running around making "dyno numbers" higher than we're shooting for on the 210mm housing, but I suspect many if not most are not making the torque we will. This will be a brutal track car that will even see some standing start launches (Optima Speed Stop events) on rather wide tires. "Over building" the diff was the smart choice...
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